xref: /linux/drivers/media/usb/cx231xx/cx231xx-vbi.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5)
1 /*
2    cx231xx_vbi.c - driver for Conexant Cx23100/101/102 USB video capture devices
3 
4    Copyright (C) 2008 <srinivasa.deevi at conexant dot com>
5 	Based on cx88 driver
6 
7    This program is free software; you can redistribute it and/or modify
8    it under the terms of the GNU General Public License as published by
9    the Free Software Foundation; either version 2 of the License, or
10    (at your option) any later version.
11 
12    This program is distributed in the hope that it will be useful,
13    but WITHOUT ANY WARRANTY; without even the implied warranty of
14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15    GNU General Public License for more details.
16 
17    You should have received a copy of the GNU General Public License
18    along with this program; if not, write to the Free Software
19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20  */
21 
22 #include <linux/init.h>
23 #include <linux/list.h>
24 #include <linux/module.h>
25 #include <linux/kernel.h>
26 #include <linux/bitmap.h>
27 #include <linux/usb.h>
28 #include <linux/i2c.h>
29 #include <linux/mm.h>
30 #include <linux/mutex.h>
31 #include <linux/slab.h>
32 
33 #include <media/v4l2-common.h>
34 #include <media/v4l2-ioctl.h>
35 #include <media/v4l2-chip-ident.h>
36 #include <media/msp3400.h>
37 #include <media/tuner.h>
38 
39 #include "cx231xx.h"
40 #include "cx231xx-vbi.h"
41 
42 static inline void print_err_status(struct cx231xx *dev, int packet, int status)
43 {
44 	char *errmsg = "Unknown";
45 
46 	switch (status) {
47 	case -ENOENT:
48 		errmsg = "unlinked synchronuously";
49 		break;
50 	case -ECONNRESET:
51 		errmsg = "unlinked asynchronuously";
52 		break;
53 	case -ENOSR:
54 		errmsg = "Buffer error (overrun)";
55 		break;
56 	case -EPIPE:
57 		errmsg = "Stalled (device not responding)";
58 		break;
59 	case -EOVERFLOW:
60 		errmsg = "Babble (bad cable?)";
61 		break;
62 	case -EPROTO:
63 		errmsg = "Bit-stuff error (bad cable?)";
64 		break;
65 	case -EILSEQ:
66 		errmsg = "CRC/Timeout (could be anything)";
67 		break;
68 	case -ETIME:
69 		errmsg = "Device does not respond";
70 		break;
71 	}
72 	if (packet < 0) {
73 		cx231xx_err(DRIVER_NAME "URB status %d [%s].\n", status,
74 			    errmsg);
75 	} else {
76 		cx231xx_err(DRIVER_NAME "URB packet %d, status %d [%s].\n",
77 			    packet, status, errmsg);
78 	}
79 }
80 
81 /*
82  * Controls the isoc copy of each urb packet
83  */
84 static inline int cx231xx_isoc_vbi_copy(struct cx231xx *dev, struct urb *urb)
85 {
86 	struct cx231xx_dmaqueue *dma_q = urb->context;
87 	int rc = 1;
88 	unsigned char *p_buffer;
89 	u32 bytes_parsed = 0, buffer_size = 0;
90 	u8 sav_eav = 0;
91 
92 	if (!dev)
93 		return 0;
94 
95 	if (dev->state & DEV_DISCONNECTED)
96 		return 0;
97 
98 	if (urb->status < 0) {
99 		print_err_status(dev, -1, urb->status);
100 		if (urb->status == -ENOENT)
101 			return 0;
102 	}
103 
104 	/* get buffer pointer and length */
105 	p_buffer = urb->transfer_buffer;
106 	buffer_size = urb->actual_length;
107 
108 	if (buffer_size > 0) {
109 		bytes_parsed = 0;
110 
111 		if (dma_q->is_partial_line) {
112 			/* Handle the case where we were working on a partial
113 			   line */
114 			sav_eav = dma_q->last_sav;
115 		} else {
116 			/* Check for a SAV/EAV overlapping the
117 			   buffer boundary */
118 
119 			sav_eav = cx231xx_find_boundary_SAV_EAV(p_buffer,
120 							  dma_q->partial_buf,
121 							  &bytes_parsed);
122 		}
123 
124 		sav_eav &= 0xF0;
125 		/* Get the first line if we have some portion of an SAV/EAV from
126 		   the last buffer or a partial line */
127 		if (sav_eav) {
128 			bytes_parsed += cx231xx_get_vbi_line(dev, dma_q,
129 				sav_eav,		       /* SAV/EAV */
130 				p_buffer + bytes_parsed,       /* p_buffer */
131 				buffer_size - bytes_parsed);   /* buffer size */
132 		}
133 
134 		/* Now parse data that is completely in this buffer */
135 		dma_q->is_partial_line = 0;
136 
137 		while (bytes_parsed < buffer_size) {
138 			u32 bytes_used = 0;
139 
140 			sav_eav = cx231xx_find_next_SAV_EAV(
141 				p_buffer + bytes_parsed,	/* p_buffer */
142 				buffer_size - bytes_parsed, /* buffer size */
143 				&bytes_used);	/* bytes used to get SAV/EAV */
144 
145 			bytes_parsed += bytes_used;
146 
147 			sav_eav &= 0xF0;
148 			if (sav_eav && (bytes_parsed < buffer_size)) {
149 				bytes_parsed += cx231xx_get_vbi_line(dev,
150 					dma_q, sav_eav,	/* SAV/EAV */
151 					p_buffer+bytes_parsed, /* p_buffer */
152 					buffer_size-bytes_parsed);/*buf size*/
153 			}
154 		}
155 
156 		/* Save the last four bytes of the buffer so we can
157 		check the buffer boundary condition next time */
158 		memcpy(dma_q->partial_buf, p_buffer + buffer_size - 4, 4);
159 		bytes_parsed = 0;
160 	}
161 
162 	return rc;
163 }
164 
165 /* ------------------------------------------------------------------
166 	Vbi buf operations
167    ------------------------------------------------------------------*/
168 
169 static int
170 vbi_buffer_setup(struct videobuf_queue *vq, unsigned int *count,
171 		 unsigned int *size)
172 {
173 	struct cx231xx_fh *fh = vq->priv_data;
174 	struct cx231xx *dev = fh->dev;
175 	u32 height = 0;
176 
177 	height = ((dev->norm & V4L2_STD_625_50) ?
178 		  PAL_VBI_LINES : NTSC_VBI_LINES);
179 
180 	*size = (dev->width * height * 2 * 2);
181 	if (0 == *count)
182 		*count = CX231XX_DEF_VBI_BUF;
183 
184 	if (*count < CX231XX_MIN_BUF)
185 		*count = CX231XX_MIN_BUF;
186 
187 	return 0;
188 }
189 
190 /* This is called *without* dev->slock held; please keep it that way */
191 static void free_buffer(struct videobuf_queue *vq, struct cx231xx_buffer *buf)
192 {
193 	struct cx231xx_fh *fh = vq->priv_data;
194 	struct cx231xx *dev = fh->dev;
195 	unsigned long flags = 0;
196 	if (in_interrupt())
197 		BUG();
198 
199 	/* We used to wait for the buffer to finish here, but this didn't work
200 	   because, as we were keeping the state as VIDEOBUF_QUEUED,
201 	   videobuf_queue_cancel marked it as finished for us.
202 	   (Also, it could wedge forever if the hardware was misconfigured.)
203 
204 	   This should be safe; by the time we get here, the buffer isn't
205 	   queued anymore. If we ever start marking the buffers as
206 	   VIDEOBUF_ACTIVE, it won't be, though.
207 	 */
208 	spin_lock_irqsave(&dev->vbi_mode.slock, flags);
209 	if (dev->vbi_mode.bulk_ctl.buf == buf)
210 		dev->vbi_mode.bulk_ctl.buf = NULL;
211 	spin_unlock_irqrestore(&dev->vbi_mode.slock, flags);
212 
213 	videobuf_vmalloc_free(&buf->vb);
214 	buf->vb.state = VIDEOBUF_NEEDS_INIT;
215 }
216 
217 static int
218 vbi_buffer_prepare(struct videobuf_queue *vq, struct videobuf_buffer *vb,
219 		   enum v4l2_field field)
220 {
221 	struct cx231xx_fh *fh = vq->priv_data;
222 	struct cx231xx_buffer *buf =
223 	    container_of(vb, struct cx231xx_buffer, vb);
224 	struct cx231xx *dev = fh->dev;
225 	int rc = 0, urb_init = 0;
226 	u32 height = 0;
227 
228 	height = ((dev->norm & V4L2_STD_625_50) ?
229 		  PAL_VBI_LINES : NTSC_VBI_LINES);
230 	buf->vb.size = ((dev->width << 1) * height * 2);
231 
232 	if (0 != buf->vb.baddr && buf->vb.bsize < buf->vb.size)
233 		return -EINVAL;
234 
235 	buf->vb.width = dev->width;
236 	buf->vb.height = height;
237 	buf->vb.field = field;
238 	buf->vb.field = V4L2_FIELD_SEQ_TB;
239 
240 	if (VIDEOBUF_NEEDS_INIT == buf->vb.state) {
241 		rc = videobuf_iolock(vq, &buf->vb, NULL);
242 		if (rc < 0)
243 			goto fail;
244 	}
245 
246 	if (!dev->vbi_mode.bulk_ctl.num_bufs)
247 		urb_init = 1;
248 
249 	if (urb_init) {
250 		rc = cx231xx_init_vbi_isoc(dev, CX231XX_NUM_VBI_PACKETS,
251 					   CX231XX_NUM_VBI_BUFS,
252 					   dev->vbi_mode.alt_max_pkt_size[0],
253 					   cx231xx_isoc_vbi_copy);
254 		if (rc < 0)
255 			goto fail;
256 	}
257 
258 	buf->vb.state = VIDEOBUF_PREPARED;
259 	return 0;
260 
261 fail:
262 	free_buffer(vq, buf);
263 	return rc;
264 }
265 
266 static void
267 vbi_buffer_queue(struct videobuf_queue *vq, struct videobuf_buffer *vb)
268 {
269 	struct cx231xx_buffer *buf =
270 	    container_of(vb, struct cx231xx_buffer, vb);
271 	struct cx231xx_fh *fh = vq->priv_data;
272 	struct cx231xx *dev = fh->dev;
273 	struct cx231xx_dmaqueue *vidq = &dev->vbi_mode.vidq;
274 
275 	buf->vb.state = VIDEOBUF_QUEUED;
276 	list_add_tail(&buf->vb.queue, &vidq->active);
277 
278 }
279 
280 static void vbi_buffer_release(struct videobuf_queue *vq,
281 			       struct videobuf_buffer *vb)
282 {
283 	struct cx231xx_buffer *buf =
284 	    container_of(vb, struct cx231xx_buffer, vb);
285 
286 
287 	free_buffer(vq, buf);
288 }
289 
290 struct videobuf_queue_ops cx231xx_vbi_qops = {
291 	.buf_setup   = vbi_buffer_setup,
292 	.buf_prepare = vbi_buffer_prepare,
293 	.buf_queue   = vbi_buffer_queue,
294 	.buf_release = vbi_buffer_release,
295 };
296 
297 /* ------------------------------------------------------------------
298 	URB control
299    ------------------------------------------------------------------*/
300 
301 /*
302  * IRQ callback, called by URB callback
303  */
304 static void cx231xx_irq_vbi_callback(struct urb *urb)
305 {
306 	struct cx231xx_dmaqueue *dma_q = urb->context;
307 	struct cx231xx_video_mode *vmode =
308 	    container_of(dma_q, struct cx231xx_video_mode, vidq);
309 	struct cx231xx *dev = container_of(vmode, struct cx231xx, vbi_mode);
310 
311 	switch (urb->status) {
312 	case 0:		/* success */
313 	case -ETIMEDOUT:	/* NAK */
314 		break;
315 	case -ECONNRESET:	/* kill */
316 	case -ENOENT:
317 	case -ESHUTDOWN:
318 		return;
319 	default:		/* error */
320 		cx231xx_err(DRIVER_NAME "urb completition error %d.\n",
321 			    urb->status);
322 		break;
323 	}
324 
325 	/* Copy data from URB */
326 	spin_lock(&dev->vbi_mode.slock);
327 	dev->vbi_mode.bulk_ctl.bulk_copy(dev, urb);
328 	spin_unlock(&dev->vbi_mode.slock);
329 
330 	/* Reset status */
331 	urb->status = 0;
332 
333 	urb->status = usb_submit_urb(urb, GFP_ATOMIC);
334 	if (urb->status) {
335 		cx231xx_err(DRIVER_NAME "urb resubmit failed (error=%i)\n",
336 			    urb->status);
337 	}
338 }
339 
340 /*
341  * Stop and Deallocate URBs
342  */
343 void cx231xx_uninit_vbi_isoc(struct cx231xx *dev)
344 {
345 	struct urb *urb;
346 	int i;
347 
348 	cx231xx_info(DRIVER_NAME "cx231xx: called cx231xx_uninit_vbi_isoc\n");
349 
350 	dev->vbi_mode.bulk_ctl.nfields = -1;
351 	for (i = 0; i < dev->vbi_mode.bulk_ctl.num_bufs; i++) {
352 		urb = dev->vbi_mode.bulk_ctl.urb[i];
353 		if (urb) {
354 			if (!irqs_disabled())
355 				usb_kill_urb(urb);
356 			else
357 				usb_unlink_urb(urb);
358 
359 			if (dev->vbi_mode.bulk_ctl.transfer_buffer[i]) {
360 
361 				kfree(dev->vbi_mode.bulk_ctl.
362 				      transfer_buffer[i]);
363 				dev->vbi_mode.bulk_ctl.transfer_buffer[i] =
364 				    NULL;
365 			}
366 			usb_free_urb(urb);
367 			dev->vbi_mode.bulk_ctl.urb[i] = NULL;
368 		}
369 		dev->vbi_mode.bulk_ctl.transfer_buffer[i] = NULL;
370 	}
371 
372 	kfree(dev->vbi_mode.bulk_ctl.urb);
373 	kfree(dev->vbi_mode.bulk_ctl.transfer_buffer);
374 
375 	dev->vbi_mode.bulk_ctl.urb = NULL;
376 	dev->vbi_mode.bulk_ctl.transfer_buffer = NULL;
377 	dev->vbi_mode.bulk_ctl.num_bufs = 0;
378 
379 	cx231xx_capture_start(dev, 0, Vbi);
380 }
381 EXPORT_SYMBOL_GPL(cx231xx_uninit_vbi_isoc);
382 
383 /*
384  * Allocate URBs and start IRQ
385  */
386 int cx231xx_init_vbi_isoc(struct cx231xx *dev, int max_packets,
387 			  int num_bufs, int max_pkt_size,
388 			  int (*bulk_copy) (struct cx231xx *dev,
389 					    struct urb *urb))
390 {
391 	struct cx231xx_dmaqueue *dma_q = &dev->vbi_mode.vidq;
392 	int i;
393 	int sb_size, pipe;
394 	struct urb *urb;
395 	int rc;
396 
397 	cx231xx_info(DRIVER_NAME "cx231xx: called cx231xx_prepare_isoc\n");
398 
399 	/* De-allocates all pending stuff */
400 	cx231xx_uninit_vbi_isoc(dev);
401 
402 	/* clear if any halt */
403 	usb_clear_halt(dev->udev,
404 		       usb_rcvbulkpipe(dev->udev,
405 				       dev->vbi_mode.end_point_addr));
406 
407 	dev->vbi_mode.bulk_ctl.bulk_copy = bulk_copy;
408 	dev->vbi_mode.bulk_ctl.num_bufs = num_bufs;
409 	dma_q->pos = 0;
410 	dma_q->is_partial_line = 0;
411 	dma_q->last_sav = 0;
412 	dma_q->current_field = -1;
413 	dma_q->bytes_left_in_line = dev->width << 1;
414 	dma_q->lines_per_field = ((dev->norm & V4L2_STD_625_50) ?
415 				  PAL_VBI_LINES : NTSC_VBI_LINES);
416 	dma_q->lines_completed = 0;
417 	for (i = 0; i < 8; i++)
418 		dma_q->partial_buf[i] = 0;
419 
420 	dev->vbi_mode.bulk_ctl.urb = kzalloc(sizeof(void *) * num_bufs,
421 					     GFP_KERNEL);
422 	if (!dev->vbi_mode.bulk_ctl.urb) {
423 		cx231xx_errdev("cannot alloc memory for usb buffers\n");
424 		return -ENOMEM;
425 	}
426 
427 	dev->vbi_mode.bulk_ctl.transfer_buffer =
428 	    kzalloc(sizeof(void *) * num_bufs, GFP_KERNEL);
429 	if (!dev->vbi_mode.bulk_ctl.transfer_buffer) {
430 		cx231xx_errdev("cannot allocate memory for usbtransfer\n");
431 		kfree(dev->vbi_mode.bulk_ctl.urb);
432 		return -ENOMEM;
433 	}
434 
435 	dev->vbi_mode.bulk_ctl.max_pkt_size = max_pkt_size;
436 	dev->vbi_mode.bulk_ctl.buf = NULL;
437 
438 	sb_size = max_packets * dev->vbi_mode.bulk_ctl.max_pkt_size;
439 
440 	/* allocate urbs and transfer buffers */
441 	for (i = 0; i < dev->vbi_mode.bulk_ctl.num_bufs; i++) {
442 
443 		urb = usb_alloc_urb(0, GFP_KERNEL);
444 		if (!urb) {
445 			cx231xx_err(DRIVER_NAME
446 				    ": cannot alloc bulk_ctl.urb %i\n", i);
447 			cx231xx_uninit_vbi_isoc(dev);
448 			return -ENOMEM;
449 		}
450 		dev->vbi_mode.bulk_ctl.urb[i] = urb;
451 		urb->transfer_flags = 0;
452 
453 		dev->vbi_mode.bulk_ctl.transfer_buffer[i] =
454 		    kzalloc(sb_size, GFP_KERNEL);
455 		if (!dev->vbi_mode.bulk_ctl.transfer_buffer[i]) {
456 			cx231xx_err(DRIVER_NAME
457 				    ": unable to allocate %i bytes for transfer"
458 				    " buffer %i%s\n", sb_size, i,
459 				    in_interrupt() ? " while in int" : "");
460 			cx231xx_uninit_vbi_isoc(dev);
461 			return -ENOMEM;
462 		}
463 
464 		pipe = usb_rcvbulkpipe(dev->udev, dev->vbi_mode.end_point_addr);
465 		usb_fill_bulk_urb(urb, dev->udev, pipe,
466 				  dev->vbi_mode.bulk_ctl.transfer_buffer[i],
467 				  sb_size, cx231xx_irq_vbi_callback, dma_q);
468 	}
469 
470 	init_waitqueue_head(&dma_q->wq);
471 
472 	/* submit urbs and enables IRQ */
473 	for (i = 0; i < dev->vbi_mode.bulk_ctl.num_bufs; i++) {
474 		rc = usb_submit_urb(dev->vbi_mode.bulk_ctl.urb[i], GFP_ATOMIC);
475 		if (rc) {
476 			cx231xx_err(DRIVER_NAME
477 				    ": submit of urb %i failed (error=%i)\n", i,
478 				    rc);
479 			cx231xx_uninit_vbi_isoc(dev);
480 			return rc;
481 		}
482 	}
483 
484 	cx231xx_capture_start(dev, 1, Vbi);
485 
486 	return 0;
487 }
488 EXPORT_SYMBOL_GPL(cx231xx_init_vbi_isoc);
489 
490 u32 cx231xx_get_vbi_line(struct cx231xx *dev, struct cx231xx_dmaqueue *dma_q,
491 			 u8 sav_eav, u8 *p_buffer, u32 buffer_size)
492 {
493 	u32 bytes_copied = 0;
494 	int current_field = -1;
495 
496 	switch (sav_eav) {
497 
498 	case SAV_VBI_FIELD1:
499 		current_field = 1;
500 		break;
501 
502 	case SAV_VBI_FIELD2:
503 		current_field = 2;
504 		break;
505 	default:
506 		break;
507 	}
508 
509 	if (current_field < 0)
510 		return bytes_copied;
511 
512 	dma_q->last_sav = sav_eav;
513 
514 	bytes_copied =
515 	    cx231xx_copy_vbi_line(dev, dma_q, p_buffer, buffer_size,
516 				  current_field);
517 
518 	return bytes_copied;
519 }
520 
521 /*
522  * Announces that a buffer were filled and request the next
523  */
524 static inline void vbi_buffer_filled(struct cx231xx *dev,
525 				     struct cx231xx_dmaqueue *dma_q,
526 				     struct cx231xx_buffer *buf)
527 {
528 	/* Advice that buffer was filled */
529 	/* cx231xx_info(DRIVER_NAME "[%p/%d] wakeup\n", buf, buf->vb.i); */
530 
531 	buf->vb.state = VIDEOBUF_DONE;
532 	buf->vb.field_count++;
533 	do_gettimeofday(&buf->vb.ts);
534 
535 	dev->vbi_mode.bulk_ctl.buf = NULL;
536 
537 	list_del(&buf->vb.queue);
538 	wake_up(&buf->vb.done);
539 }
540 
541 u32 cx231xx_copy_vbi_line(struct cx231xx *dev, struct cx231xx_dmaqueue *dma_q,
542 			  u8 *p_line, u32 length, int field_number)
543 {
544 	u32 bytes_to_copy;
545 	struct cx231xx_buffer *buf;
546 	u32 _line_size = dev->width * 2;
547 
548 	if (dma_q->current_field == -1) {
549 		/* Just starting up */
550 		cx231xx_reset_vbi_buffer(dev, dma_q);
551 	}
552 
553 	if (dma_q->current_field != field_number)
554 		dma_q->lines_completed = 0;
555 
556 	/* get the buffer pointer */
557 	buf = dev->vbi_mode.bulk_ctl.buf;
558 
559 	/* Remember the field number for next time */
560 	dma_q->current_field = field_number;
561 
562 	bytes_to_copy = dma_q->bytes_left_in_line;
563 	if (bytes_to_copy > length)
564 		bytes_to_copy = length;
565 
566 	if (dma_q->lines_completed >= dma_q->lines_per_field) {
567 		dma_q->bytes_left_in_line -= bytes_to_copy;
568 		dma_q->is_partial_line =
569 		    (dma_q->bytes_left_in_line == 0) ? 0 : 1;
570 		return 0;
571 	}
572 
573 	dma_q->is_partial_line = 1;
574 
575 	/* If we don't have a buffer, just return the number of bytes we would
576 	   have copied if we had a buffer. */
577 	if (!buf) {
578 		dma_q->bytes_left_in_line -= bytes_to_copy;
579 		dma_q->is_partial_line =
580 		    (dma_q->bytes_left_in_line == 0) ? 0 : 1;
581 		return bytes_to_copy;
582 	}
583 
584 	/* copy the data to video buffer */
585 	cx231xx_do_vbi_copy(dev, dma_q, p_line, bytes_to_copy);
586 
587 	dma_q->pos += bytes_to_copy;
588 	dma_q->bytes_left_in_line -= bytes_to_copy;
589 
590 	if (dma_q->bytes_left_in_line == 0) {
591 
592 		dma_q->bytes_left_in_line = _line_size;
593 		dma_q->lines_completed++;
594 		dma_q->is_partial_line = 0;
595 
596 		if (cx231xx_is_vbi_buffer_done(dev, dma_q) && buf) {
597 
598 			vbi_buffer_filled(dev, dma_q, buf);
599 
600 			dma_q->pos = 0;
601 			dma_q->lines_completed = 0;
602 			cx231xx_reset_vbi_buffer(dev, dma_q);
603 		}
604 	}
605 
606 	return bytes_to_copy;
607 }
608 
609 /*
610  * video-buf generic routine to get the next available buffer
611  */
612 static inline void get_next_vbi_buf(struct cx231xx_dmaqueue *dma_q,
613 				    struct cx231xx_buffer **buf)
614 {
615 	struct cx231xx_video_mode *vmode =
616 	    container_of(dma_q, struct cx231xx_video_mode, vidq);
617 	struct cx231xx *dev = container_of(vmode, struct cx231xx, vbi_mode);
618 	char *outp;
619 
620 	if (list_empty(&dma_q->active)) {
621 		cx231xx_err(DRIVER_NAME ": No active queue to serve\n");
622 		dev->vbi_mode.bulk_ctl.buf = NULL;
623 		*buf = NULL;
624 		return;
625 	}
626 
627 	/* Get the next buffer */
628 	*buf = list_entry(dma_q->active.next, struct cx231xx_buffer, vb.queue);
629 
630 	/* Cleans up buffer - Useful for testing for frame/URB loss */
631 	outp = videobuf_to_vmalloc(&(*buf)->vb);
632 	memset(outp, 0, (*buf)->vb.size);
633 
634 	dev->vbi_mode.bulk_ctl.buf = *buf;
635 
636 	return;
637 }
638 
639 void cx231xx_reset_vbi_buffer(struct cx231xx *dev,
640 			      struct cx231xx_dmaqueue *dma_q)
641 {
642 	struct cx231xx_buffer *buf;
643 
644 	buf = dev->vbi_mode.bulk_ctl.buf;
645 
646 	if (buf == NULL) {
647 		/* first try to get the buffer */
648 		get_next_vbi_buf(dma_q, &buf);
649 
650 		dma_q->pos = 0;
651 		dma_q->current_field = -1;
652 	}
653 
654 	dma_q->bytes_left_in_line = dev->width << 1;
655 	dma_q->lines_completed = 0;
656 }
657 
658 int cx231xx_do_vbi_copy(struct cx231xx *dev, struct cx231xx_dmaqueue *dma_q,
659 			u8 *p_buffer, u32 bytes_to_copy)
660 {
661 	u8 *p_out_buffer = NULL;
662 	u32 current_line_bytes_copied = 0;
663 	struct cx231xx_buffer *buf;
664 	u32 _line_size = dev->width << 1;
665 	void *startwrite;
666 	int offset, lencopy;
667 
668 	buf = dev->vbi_mode.bulk_ctl.buf;
669 
670 	if (buf == NULL)
671 		return -EINVAL;
672 
673 	p_out_buffer = videobuf_to_vmalloc(&buf->vb);
674 
675 	if (dma_q->bytes_left_in_line != _line_size) {
676 		current_line_bytes_copied =
677 		    _line_size - dma_q->bytes_left_in_line;
678 	}
679 
680 	offset = (dma_q->lines_completed * _line_size) +
681 		 current_line_bytes_copied;
682 
683 	if (dma_q->current_field == 2) {
684 		/* Populate the second half of the frame */
685 		offset += (dev->width * 2 * dma_q->lines_per_field);
686 	}
687 
688 	/* prepare destination address */
689 	startwrite = p_out_buffer + offset;
690 
691 	lencopy = dma_q->bytes_left_in_line > bytes_to_copy ?
692 		  bytes_to_copy : dma_q->bytes_left_in_line;
693 
694 	memcpy(startwrite, p_buffer, lencopy);
695 
696 	return 0;
697 }
698 
699 u8 cx231xx_is_vbi_buffer_done(struct cx231xx *dev,
700 			      struct cx231xx_dmaqueue *dma_q)
701 {
702 	u32 height = 0;
703 
704 	height = ((dev->norm & V4L2_STD_625_50) ?
705 		  PAL_VBI_LINES : NTSC_VBI_LINES);
706 	if (dma_q->lines_completed == height && dma_q->current_field == 2)
707 		return 1;
708 	else
709 		return 0;
710 }
711